Officials say two fatalities are being reported after a serious collision near Vaughan.
Multiple vehicles, including a tractor trailer, were involved in the collision on the 407 according to OPP Sgt. Kerry Schmidt.
"At this point it does look like a vehicle crossed over from the westbound to eastbound lanes, collided with vehicles heading eastbound, and the vehicles came to rest here on the eastbound side of the 407 between Dufferin and Keele. The collision is massive."
Emergency vehicles closed the highway in both directions as firefighters battled a blaze spewing black smoke over the highway.
Schmidt said the highway will remain closed for 'several, if not many, hours.'
Anyone who witnessed the crash is asked to contact police.
This comes exactly one year after a devasting fire on the 400 killed three people in a fiery crash north of Toronto.